Manufacture of parachutes



Nov. 12, 1940.

1.. P. FRIEDER 2,221,322

Filed Oct. 24, 1958 FIGB.

4 INVENTOR LEONARD R Ffi/EDEI'? M ,qM w

ATTORNEY Patented Nov. 12, 1940 UNITED STATES PATENT OFFICE MANUFACTURE OF PARACHUTES Leonard P. Frleder, New York, N. Y.

Application October 24, 1938, Serial No. 236,810

4 Claims.

This invention relates generally to improvements in parachutes, and has particular reference to improvements in the manufacture of the sails of such devices.

In order to have the greatest efficiency and safety in a parachute sail, particularly a large sail, it is desirable to have the sail made up of a number of gores each composed of a single piece of fabric, that is, without either transverse or radial seams inthe gores. As is well known,

these sails are usually composed of gores which are substantially triangular in shape and are secured together at their edges. Along, or extending from, the seams connecting the gores 5 are shroud lines which are attached at their ends to some form of load support.

It has heretofore been impossible to, out long gores without wasting substantially one-half of the material, or making each gore from pieces of material sewed together. One object of the invention is to provide a way in which such long continuous gores, without piecing, may be produced. As a resulting advantage, the sail may be made up of a large number of long and narrow gores which, with their connecting seams and shroud lines, will distribute the load along numerous lines extending radially of the sail with the fabric between the seams free to per-- 80 form its sail function without localized stresses or strains between the lines of load suspension due to interferences set up by transverse, radial or oblique seams.

With the foregoing and other objects in view,

35 the invention consists in providing a novel fabric from which long narrow gores may be out without patching or'piecing and without waste of the material; and the method of employing that fabric in the manufacture of parachute sails. The invention is hereinafter explained with reference to the drawing which accompanies and forms a. part of this application, the novel features being pointed out in the claims appended hereto:

45 In said drawing:

Fig. 1 illustrates diagrammatically the form of fabric employed and the manner in which it may be cut into gores for a parachute sail;

Fig. 2 illustrates another method of cutting 5 the fabric whereby a great number of gores may be cut at a time;

Fig. 3 illustrates the manner in which the gores are joined together to make up a parachute sail.

55 The fabric illustrated in Fig. 1 is in tubu ar!" form and is woven without any longitudinal seams in a manner well known in the weavin art. In doing such weaving the looms will produce a tubular fabric which when flattened will have about the same width as the single strip 5 fabric produced on the same loom. That is to say, there will be in effect two plies of fabric when the tube is flattened with no selvage or other longitudinal interruptions in the material. This tubular fabric can be woven in various l0 widths but in Weaving for a gore of certain dimensions it is important to proportion the width or diameter of the tube so that it will, when out as hereinafter described, produce multiples of two gores.

In cutting the fabric the method indicated by the dot and dash lines It] and H in Fig. 1 may be employed. A section of the tube long enough for a gore is laid on a cutting table and secured and then preferably one or more templates laid upon .the fabric and used for guides in cutting, which will, in the practice illustrated in Fig. 1, produce four gores between each pair of cross cuts ll, all of which will be alike in shape and relative arrangement of the warp and filler threads of the material. It is obvious, of course, that there are no limits imposed upon the length of the gores which may be cut in the manner described, and that the only limit upon the base width of each gore (represented by one of the lines II) is the width capacity of the loom. It is also obvious that no waste is involved in cutting and that the gores may be then arranged and attached together along their long edges to make up a sail as illustrated in Fig. 3.

Another method of cutting the tubular fabric to produce simultaneously'a larger number of gores is illustrated diagrammatically in Fig. 2. In this method the tubular fabric is folded back and forth in long lengths so as to provide a pile 40 as illustrated in the figure last mentioned. Templates are then applied to the pile and the pile compressed, after which any of the usual cutters may be employed to cut through the pile along the diagonal lines l2 and I3 as indicated. The material is then cut through the looped ends or the power cutter used to shear off the folds atthe ends of the pile, thereby severing the pile into a great number of gores each exactly alike as to dimensionsshape and material.

In cutting gores from the material of the prior art, that is, the straight strip of fabric, it is impossible to out long gores without great waste 9 the material or without patching pieces togather to make up some of the gores if all of the material is used. This is because there is no parachute fabric in existence which is wide enough, and no loom which can weave a strip 6 wide enough, to permit cutting the gores crosswise of the strip along diagonal lines to provide triangular one-piece gores if the gores are to be of any great length. The present practical limit of looms for weaving strips of light weight fabrics suitable for parachute sails, is about seventy inches. Gores cut crosswise of such strip and along triangular lines could not be of any greater length than the strip width so, in order to make a parachute sail in which the gores are longer than the width of the strip, it is necessary to make the gore from pieces connected together by seams which when the gores are assembled in the sail will run transversely between the seams which connect the gores together. For example. the gores of the standard man parachute are thirteen and a half or more feet long from base to point in the completed sail, so several of such cross seams would appear in each gore. Larger sails would necessitate even more of such seams.

Ii, on the other hand, the long gores are cut lengthwise oi the strip then one half of the material must be wasted, or the left-over pieces must be connected together along their straight edges by a seam to form a triangular gore and this seam will then extend radially of the sail along the middle of the gore. In other words, half of the gores would be 01' seamless material and the other half of the gores would be in two pieces connected together by a radial seam. Also, the intermediate gores having these radial seams will, because of the amount taken up in forming such seams, be of different widths than the gores in which no such seams are to be found and would result in unsatisfactory load distribution on the 40 sail.

This can be appreciated by taking the top layer in Fig. 2 of the drawing as representing what will happen if the gores are cut lengthwise of a strip. The gore 15 between the two diagonal 45 lines I! and I3 will be continuous and seamless, but this will leave what may be termed two half gores It at either side. To utilize this material at all the two half gores will have to be joined together along their straight edges I! to make up 60 a gore. This seam, which will extend radially of the sail if the seamed gore is used, is, because of its addition to the bulk, and the localization of stresses along a radial line, as well as the cost of making a strong seam, so objectionable that it 55 would be preferable to dlscard'these half gores It even though this means a loss of about half of the costly fabric used in parachute manufacture.

, The shroud lines used in the manufacture of 6 parachute sails from gores cut and assembled in the manner described, are preferably such as are shown and described in application Serial No. 236,809, filed October 24, 1938, by the present applicant. Such shroud lines are so constructed that, in addition to other advantages, a great number of them may be employed in the making up of large sails without interfering with the folding of the parachute in a container or pack and will, both because of their structure and the way they function, make it possible to use a great many more shroud lines than has heretofore been practical without a disadvantageous increase in bulk when the parachute is packed.

From all of the foregoing, it is apparent that it is possible to produce a parachute having a sail composed of single piece gores of unlimited length and without waste of any of the material employed. For example, in parachutes which are large enough to support a plane, a large number of such narrow base long gores may be employed with a multiplicity of shroud lines or suspension lines to distribute the stress and each of these gores will have no seams extending either radially or transversely to localize stresses and increase the bulk of the parachute in its pack or container.

While the invention has been explained somewhat in detail, it will be obvious to those skilled in the art that various changes and modifications are possible, all of which come within the claims which follow.

What is claimed is:

1. That method of manufacturing parachute sails which comprises laying off on a flattened tube of fabric base lines spaced apart distances of more than twice the width of the flattened tube, laying off on the flattened tube diagonal lines of equal length converging from one base line to an apex at the next base line, and cutting through the flattened tube along said base lines and said diagonal lines to produce without waste of material a plurality of single piece gores each having a base equal to the width of the flattened tube and a length of more than twice said width.

2. A method of manufacturing parachute sails from a tube of fabric of a diameter which, when the tube is flattened, has a width which is substantially the base width of a gore, comprising cutting across the flattened tube to divide the tube into sections each more than twice as long as the width of the flattened tube, cutting each section along converging diagonal lines at equal angles to the cross cuts to provide without waste of material, a plurality of substantially triangular single piece gores all of which are substantially alike and each having a length which is more than twice the length of the cross cut and securing a plurality of said gores together to make up a sail.

3. That method of manufacturing parachute sails which comprises flattening a tubeof silk parachute fabric, cutting the flattened tube crosswise to divide the tube into sections each more than twice as long as the width of the flattened tube, and cutting through each section of the flattened tube along diagonal lines of equal length converging from one cross cut to the next cross cut whereby to produce from each section, without waste of material, a plurality of triangular gores all substantially alike and each more than twice as long as its base width.

4. That method of manufacturing parachute sails which comprises flattening a tube of silk fabric, cutting the flattened tube crosswise to divide the tube into sections each more than ten feet long, and cutting through each section of the flattened tube along diagonal lines of equal length converging from one end of a section to an apex at the other end of the section whereby to produce without waste of material a plurality of single piece parachute gores all of which are substantially alike and all of which are over ten feet in length.

LEONARD P. FRIEDER. 

